思想:
定义下标start=0和end=len(numbers-1),将numbers[strat]和numbers[end]相加,相加的结果和target进行比较。若大于targe则end=end-1,若小于target则start=start-1,若相等则返回start+1和end+1。由于数组是有序数组,从数组头和尾元素相加开始判断和target的大小关系,这样可以快速找到目标元素
class Solution:
def twoSum(self, numbers, target):
"""
:type numbers: List[int]
:type target: int
:rtype: List[int]
"""
start, end = 0, len(numbers) - 1
while start < end:
s = numbers[start] + numbers[end]
if s > target:
end -= 1
elif s < target:
start += 1
else:
return (start + 1, end + 1)